FSF-1 'Sea Fighter'

Sea Fighter is an experimental littoral surface combat vessel under development by the United States Navy.

The vessel is of a catamaran design capable of high speed and of operations on open ocean and in shallow waters. The vessel is being developed under the program title Littoral Surface Craft-Experimental (LSC(X)) with a hull type designation Fast Sea Frame. The first vessel has been assigned the hull number FSF 1 and also has been referred to as the X-Craft.